Kāinga Ora has proposed halving the team it set up to meet Māori housing needs and fulfil Treaty of Waitangi obligations.
Te Kurutao Group Māori has 48 full-time staff, and the organisation is consulting with them on a plan to shed 27 roles.
It brings the total number of jobs proposed to be slashed at the agency to 232 as part of wider public sector cost-cutting measures.
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The Public Service Association (PSA) said Te Kurutao helped Kāinga Ora fulfil its legislative function to "understand, support, and enable the aspirations of Māori in relation to urban development".
Ministry of Housing and Urban Development statistics showed 39 percent of Kāinga Ora tenants were Māori.
"This is outrageous at a time when it's never been more important to provide healthy, secure and affordable housing for Māori if we are to make real inroads into poverty in this country," said PSA Te Kaihautū Māori Janice Panoho.
"Te Kurutao is the team of experts who bring a critical te ao Māori perspective to housing challenges, assisting other staff at Kāinga Ora and advising Māori on funding and planning issues."
Their work supports Kāinga Ora to turn ideas into projects that deliver affordable, quality housing for hapū and Māori organisations, she said.
Kāinga Ora said Te Kurutao Group Māori was one of its teams affected by reduced Budget funding.
Its change proposal "will align with both the legislative obligations we are required to meet and the new funding levels", said ringa raupa deputy chief executive Te Kurutao Group Māori, Te Ariki Pihama.
'Disappointing' - Māori housing advocate
Having a team within Kāinga Ora dedicated to Māori was vital, said Māori housing advocacy group Te Matapihi acting chief executive Ali Hamlin-Paenga.
Te Matapihi and Te Kurutao had a "very strong relationship" and worked together to support Māori and ensure their housing needs were met, she said.
"[Te Kurutao] understand te ao Māori, they understand tikanga, they understand... the whenua, the papakāinga, they know what papakāinga means to whānau," she said.
"We often are told that... 'everybody understands', and 'everybody will work with you to achieve the housing aspirations of people', but often that's not the case - and so having a Māori focus and the allies across the Crown agencies is hugely important."
With that in mind, the cuts were "disappointing", Hamlin-Paenga said.
"There's a theme across all of our Crown agencies that is coming to light here... in respect of departments within Crown agencies that have been set up to support Māori."
But Te Matapihi would continue to "work hard together" with the staff that remain in Te Kurutao to ensure the best outcomes for Māori, she said.